I believe it is the rudder which is not always stripped rather than the tail itself, due to need to balance it after painting (for this reason rudders are painted before fitting in the factory)
This said, I would be surprised if paint from pre 1997 was still under there 25 years later....

EDIT then again there are some photos online (I think at Cardiff) of 747s with the original world tails livery visible below the current livery on the fusalage under the trim adjustment area of the tail section....